Construction crews in recent weeks have begun erecting concrete walls for the PPL Center, the 8,500-seat arena that will become home to the Philadelphia Flyers' minor league affiliate when it opens in September 2014.

Located at Seventh and Hamilton streets, the arena has been touted by city officials as integral to downtown revitalization efforts.

The arena block will include a seven-story hotel, two multi-level office buildings and a mixed-use retail and apartment complex, all of which is being built by City Center Lehigh Valley, a development group headed by J.B. Reilly.

The arena’s project manager previously said construction is ongoing six days a week, 12 hours a day. The number of workers at times is expected to rise to 500, including various contractors, the manager previously said.

Including hockey, concerts and other events, the arena is expected to be in use 120 days a year once it opens.